36 Allgemeine Morphologie, Phylogenie, Descendenztheorie. 



Allgemeiue Morphologie, Phylogenie, Desceiidenztlieorie. 



134-) Johnson, R. H., The Malthusian principle and natural selection. 

 In: Amer. Natural. 46, S. 372—376, 1912. 



The reproductive rate of any species is not an arbitrarily large number, but 

 is an adapted quality, according to the needs of the species. "The number of 

 progeny which is best adapted to the needs of the species is that number 

 which is large enough to sustain the losses from all non-sustentative causes of 

 death, but not large enough to invoke death by starvation." It is erroneous to 

 suppose that any species is living up to the limits of its food supply. Otlier 

 causes of death continually keep the species below this limit. 



Gates (London). 



135) Bailey, Irving TV., The evolutionary history of the foliar ray in the 

 wood of the Dicotyledons: and its phylogenetic significance. In: Annais 

 of Botany, Vol. 26, Heft 2, S. 647—661, pls. 62—63, 1912. 



The writer begins with the hypothesis that in the stems of the "Beeches"' (Fagales) the 

 uniseriate ray is the most primitive type of structure, from which large sheets of ray tissue 

 have been developed by a process of aggregation and fusion. This view is based upon 

 the comparative developmental anatomy of living and fossil plants, the phylogenetic sig- 

 nificance of seedlings and of wounded regions. Alter further comparative study of the 

 Oaks, Beeches and allied forms the foUowing conclu^ions are stated: 1. The central- 

 cylinder of primitive Angiosperms was a siiahonostele with streng secondary growth. 2. The 

 wood of this stem possessed only uniseriate rays, like the wood. of Conifers. 3. During 

 Mesozoic times sheets of storage tissue were built up from aggregations of uniseriate 

 rays about the leaf-traces of evergreen Angiosperms. 4. This type of ray has persisted 

 in certain species of primitive families, such as the Fagales. 5. As geological climates 

 changed, the conditions of storage in Dicotyledons stems were modified, and in most 

 modern trees the uniseriate rays of the aggregating mass of ray tissue have become dif- 

 fused uniformly through the stem and in must cases the evidence of tbeir former rela- 

 tion to the leaf traces has disappeared. 6. In certain forms the aggregate type of rays 

 are compounded into homogeneous masses of jjarenchyma. 7. In other families a rever- 

 sion to the primitive uniseriate ray has taken jjlace. 



These views require fundamental modifications in the existing conceptions of the 

 origin and development of the woody cylinder in Angiosperms. Gates (London). 



Hierzu: Nr. 130, 147, 179, 183, 202, 222, 230. 



Physiologie der Zellen, Gewebe und Organe. 



/136) Waglier, A., Vorlesungen über vergleichende Tier- und Pflanzen- 

 kunde. Zur Einführung für Lehrer, Studierende und Freunde der Naturwissen- 

 schaften. Leipzig (Wilhelm Engelmann) 1912. 8°. VIII u. 518 S. 



Diese Vorlesungen sind aus dem Gefühle der Notwendigkeit entsprungen, 

 dem Studierenden bei jedweder Behandlung der wissenschaftlichen Lebensprob- 

 leme Tier und Pflanze in möglichster Parallele vorzuführen. Sie sollen Werken 

 wie 0. Hertwigs „Allgemeiner Biologie" und Verworns „Allgemeiner Physio- 

 logie" ergänzend an die Seite treten, indem sie nicht die Zelle und ihre Funk- 

 tionen, sondern den Organismus und seine Funktionen, einerseits als Tier, anderer- 

 seits als Pflanze, zum Gegenstand haben. Dabei hat sich Verf. die Beschränkung 

 auferlegt, nur die der Lebensbehauptung dienenden Funktionen und Einrichtungen 

 zu behandeln und die der Fortpflanzung dienenden außer acht zu lassen, eine Be- 

 schränkung, die dadurch gerechtfertigt wird, daß über die Fragen der Fortpflan- 

 zung schon reichlicher zusammenfassende Schriften vorliegen. Das Werk stellt 

 sich somit in der Hauptsache als eine eingehende Vergleichung zwischen Tier 



